New Ohio-developed liquid crystal test will aid in hunt for food pathogens

View full sizeThomas Ondrey, The Plain DealerIn a dust-free "clean room" at Crystal Diagnostics' Kent manufacturing facility, lab technician Jake Ruby inspects glass that will be used in a new food pathogen sensor that employs liquid crystal technology.

KENT, Ohio — Liquid crystals, the Ohio-pioneered technology that enables smart phones and flat-screen TVs to light up, are now poised to transform food testing, quickly illuminating the presence of bacteria and other dangerous pathogens in meat and produce.

Officials of the Kent- and Colorado-based technology start-up Crystal Diagnostics on Wednesday unveiled a new approach to detect food contaminants such as E. coli, which sicken tens of millions of Americans annually.

The biosensor takes advantage of the strange properties of liquid crystals – tiny molecules that can flow like water or freeze in place like ice, depending on how they're manipulated.

Current food-borne pathogen tests can take hours or days to pinpoint a single contaminant. Using liquid crystal technology developed at Kent State University and the Northeast Ohio Medical University, the new MultiPath tester can detect multiple pathogens in a half-hour or less, company officials said.

A demonstration Wednesday identified salmonella and E. coli in a sample in about 19 minutes.

Despite government-required and voluntary food industry testing, the CDC estimates that each year 48 million Americans get sick, 128,000 need hospital care, and 3,000 die from food-borne diseases. The dangerous micro-organisms come from animals' bodies, from the environment, and from food handlers' poor hygiene.

View full sizeThomas Ondrey, The Plain DealerDan Minardi, Crystal Diagnostics' president and chief technology officer, shows the cassette that holds food samples to be tested in the company's new biosensor.

Existing tests basically involve either coaxing a sample of a suspected pathogen to grow in a lab dish, which can take several days, or making copies of a possible contaminant's DNA, then using chemical probes to identify its unique signature. The latter process is quicker, but still takes hours.

That may not seem like a lot of time. But in April the U.S. Department of Agriculture announced plans to require that meat and poultry producers not distribute their goods until government pathogen test results are known, a change intended to reduce the amount of unsafe food that winds up on store shelves.

The longer the test-processing time, the more costly storage space a food producer would need to hold their wares. Delays also could affect food freshness and sell-by dates.

Crystal Diagnostics' test, which has been in development for five years and is covered by nine patents, relies on the ability of liquid crystals to block light.

To start, a technician mashes up a dollop of the food to be tested – a chunk of hamburger meat or a bit of melon, for example. The liquid from the mush is mixed with a cocktail of tiny plastic beads coated with special proteins called antibodies.

Each antibody can recognize and latch on to a specific kind of pathogen, like a smart bomb that homes in on a particular target. If the hamburger juice contains E. coli, for instance, that bacteria's antibodies and their plastic carriers will stick to it, forming clumps.

That's where the liquid crystals come in. The technician adds a pinch of crystals to the food-antibody mix, then slides the sample into the tester's electronic "reader."

At the right temperature, liquid crystals can be made to line up in ordered rows, like slats in a Venetian blind. The formation, called a matrix, is so tight that light can't pass through it, just as a closed blind keeps out sunlight.

But if there are clumps made of antibody-coated beads and their target bacteria in the matrix, the liquid crystals can't align tightly enough to prevent focused light from shining through. NEOMED scientist Gary Niehaus, a co-inventor of the process with Kent State researchers Christopher Woolverton and Oleg Lavrentovich, likens the effect to tennis balls being stuck between the Venetian blind's slats.

An optical detector registers the presence of food contaminants as points of light on a dark background. The results are beamed to a smart phone or iPad.

"It's an elegant system," said Crystal Diagnostics CEO Paul Repetto. Results are 15 to 30 percent quicker than the fastest existing food pathogen test, he said, with comparable accuracy and greater versatility, since the MultiPath can detect several contaminants in the same test run.

The company currently is "beta-testing" its biosensor, getting feedback from the food processing companies and commercial food testing labs who are its potential customers. Production in Crystal Diagnostics' Kent manufacturing plant should begin next year, Repetto said.

Kent State, where chemistry professor Glenn Brown realized liquid crystals' potential nearly 50 years ago and formed the university's Liquid Crystal Institute, is recognized as the birthplace of modern liquid crystal displays.

Brown died in 1995, but, as Kent State president Lester Lefton said at Wednesday's rollout of the newest liquid crystal innovation, somewhere "I'm sure Glenn Brown is smiling."

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